Arc incandescent lamp



Dec. 6, 1927. 1,651,398

c. F. LORENZ ARC INCANDESCENT LAMP Filed March 26, 1923 2 Sheets-Sheet 1 24 \21 I" 2/ o I 20 2O @25 was- INVENTOR CHARLES F LORENZ Dec. 6,1927. 1,651,398

C. F. LORENZ ARC INCANDES CENT LAMP Filed March 2 1925 2 Sheets-Sheet 2 FIGIO.

INVENTOR CHARLES F LORENZ.

A ORNEY j parent as the description proceeds.

Patented Dec. 6, 1927.

UNITED STATES PATENT OFFICE.

CHARLES FREDERICK LORENZ, 01 EAST ORANGE, NEW JERSEY, ASSIGNOB TO WEST- INGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

ARC INOANDESCENT LAMP.

. r Application filed March 26, 1928. Serial No. 627,544.

This invention relates to electric incandescent lamps and more particularly to lamps adapted for motion-picture projection or those having concentrated light sources.

An object of my invention is the provision of an electric incandescent lamp which utilizes, in its construction, the principle of black-body radiation.

A further object of my invention is the provision of an electric-discharge lamp having one of its electrodes composed of a plurality of cells.

A further object of my invention is the provision of an electric-discharge lamp in which the electrodes are so ositioned within the lamp as to be partial y heated by reflected heat and light, whereby the energy put into the lamp may be conserved.

A still further object of my invention is the provision of a projection lamp which employs, in its construction, the black-body principle and also conserves some of the energy put into the lamp by reflection of the radiation upon the light source.

Other objects of the invention will be ap- In motion-picture projection. lamps of the type which are more commonly used, a concentrated light source is provided by employing a series of helical coils disposed in a formed coils. The arrangement of the filament in this manner gives a solid source of light.

It has been observed in these lamps, that the interior of the c011 appears to have a greater brightness than its outside. This effect is due to the reflections of light within the coil, and is referred to in the literature as the black-body effect. It is the purpose of my inventionto utilize this principle in designing a lamp for projection purposes.

In order that the energy which is dissipated in the form of radiant energy may be conserved, I may employ, as illustrated in one embodiment of my lamp, a reflector which is combined with the bulb thereof. The light and heat striking this reflector is directed backwardly upon the electrodes and the heat is thus conserved.

Referring now to the drawings, which radiator principle but in Fig. 6 is a modification in which the cel-' lular construction is obtained by bending a corrugated strip of metal into a coil;

F1 7, 8 and 9 show other arrangements of t e electrode to secure black-body effects.

Fig. 10 illustrates a form and arrangement of electrodes embodying the blackwhich each electrode supports a portion of the lamellar elements which combine to form the cellular structure; and,

Fig. 11 is atransverse sectional view of the lamp taken on line XI-XI of Fig. 10

In. the lamp illustrated in Fig. 1, 12 indicates an envelope of spherical shape havin an inner coating 13 of a reflecting materiafi such as silver or the like. A portion of this coating material is omitted from a section 14 of the bulb in order that the light which is generated within the envelope may be capable of emission therefrom.

The bulbor envelope 12 may be sealed to prevent any gas or air from passing into the same. The interior of the bulb i" filled with a gaseous or inertenvironment which may be at such a pressure that an electrical discharge maybe sustained between the electrodes, subsequently to be described. Ordinarily, a pressure of 600 millimeters of mercury is sufficient. I prefer to employ, as the gaseous medium, a gas which is mert with respect to the electrode material. A suitable gas is argon, nitrogen, neon, helium, and the like, or mixtures thereof.

The light is secured by heating a pair of electrodes 15 and 16 to incandescence; this being accomplished by passage of an electrical dischar e between the same. The current for this ischarge may conducted to the electrodes by the eading-ln wires 18 and 19, which latter ma also furn sh support for the electr es. If desired, the electrodes 15 and 16 may be supported by auxiliary means (not shown).

In order that the arc may be passed between the electrodes 15 and 16, they are aced apart an appropriate distance, such distance depending upon the particular gas pressure employed, character and aurrty of the gas, electrode material, etc. 1th a gas ressure of 600 millimeters of mercury, the distance should preferably be about 3 millimeters.

The electrode 15, in the embodiment illustrated in Fig. 1, comprises a narrow band of a conductive material, such as tun sten or the like. This band is bent in the orm of a circle, open at its lower portion 17, and may be retained in this pos tion by any desired means or may be given this shape initiall Within the space enclosed lay the clectrod 15, is positioned the electro e 16, the latter being of a special construction, about to be described, in order to obtain the black-body efiect.

In the embodiment illustrated in F1g. 1, the electrode 16 is com osed of a pluraht of cells or hone com structure 20 whic 1 are formed by t e assembly of a number of small tubes 21 composed of a refractory metal, such as tungsten or the like. These tubes may be held in position in any desirable manner, for exam le, by shrinkin a band 21 thereabout. t is preferred t at they be arranged in accordance with some symmetrical design. In Fig. 2, this design consists of an outer circle of these tubes, an inner circle of tubes and a single tube positioned at the center of these circles.

This construction provides a series of concentric cells. If desired, these cells may be closed at their rear ends in order to secure a better reflection of the light therein.

To minimize the pro ortlon of the radiation from the sides wit respect to the total radiation and, at the same time, to retain the black-body effect, I find it preferable to construct the cells so that their depths are great in comparison with their individual widths,

and also to have the depth of the cells shallow in comparison with the total width of the group of cells constituting the electrode.

In Figs. 3, 4, 7, 8 and 9, the cellular or honeycomb structure is formed by dividing the tubular member 21' into a number of smaller openings or cavities 20 byvpartitlons or lamellar elements 22. Referrm particularly to Figs. 3 and 4, the partitions 22 are arranged radially within the cylinder 21 and may be secured in their adjusted positions by casting a block 24 of refractory metal about their lower edges. Other methods may be employed for securingvthe partitions in their adjusted positions. ith this construction, one end of the cells will be closed, thus increasing the black-body effect. In Figs. 7 and 8, the tubular member 21' is given a square confi ration, and the space enclosed thereby is divided into a plurality of cells 20 by arranging the artitions parallel to the walls of the tu ular member 21. 'The partitions in Fig. 7 cross each other at ri ht angles and may be secured in their a justed positions by providing a slotted arrangement similarly to that provided in the partitions used in egg crates. In Fig. 8, the arrangement of the partitions is somewhat similar tothat illustrated in Fig. 7 except for the omission of the cross partitions. In Fig. 9, the partitions 22 are given a saw-tooth formation and may be separated by suitable plates 23'.

Another arrangement of cells may be secured by the construction illustrated in Fig. 5 wherein the cells 20 are formed by disposing a plurality of cylinders 21, one within another but spaced apart. This construction provides a series of circular cells or openings 20. In Fig). 6, the cellular structure is formed by ending a corrugated band 23 upon itself in the form of a coil. The corrugationsfrovide cells 20. The wound strip is retaine or cylinder 21'.

A further modification of my invention is illustrated in Fig. 10 in which the cellular structure for producin the black-body effeet is obtained by ma ing each electrode a counter part of the other. In the embodiin its position by an outer tube ment illustrated, each of the electrodes is formed of a strip of tungsten metal 25 having projecting, at right angles from one side thereof, a plurality of flat strips 26 of the same width as the body material 25. The

strips 26, in assembling the electrodes within the lamp, are inserted in the spaces between strips 26 of the op osed electrode. In thismanner, the space etween the strips 26 ofthe one electrode is divided into two cells by a single strip 26 of an opposed electrode.

This constructlon enables the electrodes to be assembled with greater facility and simplifies considerably their construction.

A lamp of this type may find considerable usage as a rojection lamp and, to this end, the electro es are illustrated as being disposed in a lamp having a tubular envelope 27. Electrodes 25 are connected, by leadingin wires 28 and 29, to base 30 and center contact 31, whereb current ma be supplied to to the electro es and -an e ectrical discharge caused to take place therebetween.

Various modifications will suggest themselva to those skilled in the art, but I contemplate all such modifications as come within the spirit of my invention as defined by the scope of the appended claims.

. other of said electrodes being dispo What is claimed is::

1. An electric lamp comprising an envelope having'an .inert atn o here therein, a concentrated light source, said light source comprising a pair of concentrically disposed electrodes Within said envelope, the inner electrode comprising a plurality of lamellar elements adapted to produce black bodyradiation.

2. An electric lamp comprisingan envelope having an inert atmosphere therein, a concentrated light source comprising a pair of electrodes within said envelope, one of said electrodes comprising an-enclosing band of conducting metal, the other of said electrodes being disposed within the space enclosed b the first electrode and comprising a plurahty of lamellar elements so disposed with set to each other as to form a plurality 0 wells or pockets. 4

3. An electric lamp comprising an envelope having an inert atmosphere therein, a

concentrated light source comprising a pair of electrodes within said envelope, one of said electrodes comprising a band of conducting metal bent to arcuate shsazplqtltile wit in the space enclosed b the first electrode and comprising a plura ity of lamellar ele= ments so-disposed withirespect to'each other lope having an inert atmosphere therein, a

concentrated light source comprising a pair of electrodes within said envelope, one of said electrodes comprising a ring shaped band of conducting metal, the other of said electrodes being disposed within the space enclosed by the first electrode and comprising a plurality of lamellarelements so disposed with respect to each other as to form a plurality of wells or pockets, said pockets being of greater de th than width and having their longitu inal axes substantially parallel to the direction in which the light is rojected. n testimony whereof, I have hereunto subscribed my name this 24th day of March, 1923. V

CHARLES FREDERICK LORENZ. 

